Flask



FIG. 1 is a front side elevation view of the flask of the present design, the left, right and rear side views being the same.

FIG. 2 is a top plan view of the flask of FIG. 1; and,

FIG. 3 is a perspective view of the flask of FIG. 1, taken from the top and front. 

CLAIM The ornamental design for a flask, as shown and described. 